Mercedes-Benz's range-topping S-Class now has a "3 liters per 100 km" car. Hot on the heels of the all-electric SLS AMG supercar, the S 500 Plug-In Hybrid packs an electric motor powered by an externally charged lithium-ion battery. The plug-in combines up to 19 miles (30 km) of emissions-free commuting with the acceleration and performance expected of an S-Class.